Testing Blood Sugar And Ketones: A Simple Guide

Testing blood sugar and ketone levels is important for people on the keto diet to understand their metabolic health and prevent diabetes. Blood glucose, or blood sugar, is the amount of sugar circulating in the blood. It rises and falls when we eat food, and a high-carb meal will cause a bigger spike than a low-carb, high-fat meal. The keto diet is a metabolic state that can only be achieved when the body is deprived of carbohydrates, so blood sugar levels are regulated on this diet. However, blood sugar does not indicate whether someone is in ketosis, but it can be correlated with ketone levels in the body. Testing blood sugar can give people insights into their body's response to specific foods, and help them understand their insulin sensitivity. Blood glucose monitors are relatively affordable and easy to find.

How to test blood sugar

Testing your blood sugar levels is an important part of managing diabetes. There are several ways to test your blood sugar levels, including a glucose meter, a continuous glucose monitor (CGM), and an HbA1c test.

Glucose Meter

The most common type of blood sugar monitoring involves using a glucose meter and test strips. This is known as a "finger stick check". You prick your fingertip with a small needle called a lancet to get a drop of blood. You then place the drop against the test strip in the glucose meter, and the meter shows your blood sugar level within seconds.

Continuous Glucose Monitor (CGM)

A CGM involves wearing a device that measures your glucose levels 24 hours a day. The device uses this data to form a graph that shows how your blood sugar levels change over time. Most CGM devices use a tiny sensor that you insert under your skin to measure glucose levels in the fluids between your body’s cells (interstitial fluid).

HbA1c Test

The HbA1c test estimates your average blood glucose levels over a period of time. For this test, a doctor collects a blood sample by drawing blood from a vein in your arm and sends the sample to a lab for testing. At-home HbA1c tests are also available, which can be helpful if you cannot easily access in-person doctor visits.

When to Test Your Blood Sugar

You may need to check your blood sugar several times a day, depending on your individual circumstances. Common times to test your blood sugar include before meals, after meals, before and after exercise, before driving, and when you think your blood sugar levels are low. It is also important to check your blood sugar when you experience symptoms of low or high blood sugar.

What is a normal blood sugar level?

Blood glucose, or blood sugar, is a primary marker for determining the risk of diabetes. The higher your blood sugar, the higher your risk factors. However, blood sugar is not just a marker for diabetes; as blood-glucose levels rise, so does the risk for many other life-threatening conditions, most notably heart disease.

The best way to mitigate your risk is to keep your blood sugar levels within a normal range. The answer to what is a normal blood sugar level is, however, controversial. The American Diabetes Association (ADA) delineates certain levels as "normal blood sugar levels", but the ADA's "normal" may not mean "optimal".

For example, according to the ADA, a normal fasting blood glucose (FBG) level is under 100 mg/dL (5.6 mmol/L). However, a large observational study found that those with FBG levels from 95 to 99 mg/dL were 2.33 times more likely to develop diabetes than those with FBG levels below 85 mg/dL. This suggests that optimal fasting blood glucose is likely somewhere below 85 mg/dL.

Similarly, the ADA considers a normal Hemoglobin A1c (HbA1c) level to be under 5.7%. However, a study found that those with HbA1c levels under 5% had significantly lower levels of heart disease than those in the mid-5% range. This indicates that an optimal HbA1c level is likely somewhere below 5%.

In terms of postprandial blood glucose (blood sugar level after a meal), as a general rule, the smaller and shorter the spike in blood sugar, the better. Try to keep blood sugar spikes to under 30 mg/dL over the baseline at one-hour post-meal. By three hours after eating, you should be back near your baseline. This indicates that insulin, the hormone that regulates blood sugar, is doing its job.

It is important to note that fasting blood sugar and postprandial blood glucose measurements are not the most reliable measures of metabolic health. Factors such as stress and lack of sleep can cause the liver to release significant amounts of glucose into the bloodstream, potentially impacting test results. That is why, in addition to blood glucose levels, it is recommended to measure HbA1c (average blood glucose over 2-3 months) and insulin levels.

What to do if your blood sugar is low

If you have low blood sugar, it is important to act quickly to treat it. Low blood sugar, also known as hypoglycaemia or a hypo, usually affects people with diabetes who take insulin or other diabetes medications, but it can sometimes occur in those without diabetes. It is important to check your blood sugar level if you are experiencing symptoms of low blood sugar, and if your level is below 4 mmol/L, you will need to take steps to treat it.

• Consume something that will quickly raise your blood sugar. This could include a small glass of fruit juice or a sugary fizzy drink, glucose or dextrose tablets, jelly babies, or glucose gel.
• Check your blood sugar level again after 10 to 15 minutes.
• If your blood sugar is still below 4 mmol/L, have another sugary drink or snack and check again after 10 minutes.
• Once your symptoms have improved and your blood sugar is above 4 mmol/L, eat something that will keep your blood sugar stable for longer, such as biscuits, a sandwich, or your next meal.

If someone is experiencing severe low blood sugar and becomes unconscious:

• Do not give them any food or drink as they will not be able to swallow safely.
• Put them in the recovery position.
• If available and if you know how to use it, give them a glucagon injection straight away.
• If they start to recover within 10 minutes of the injection and can swallow safely, give them something to eat or drink to raise their blood sugar.
• Stay with them until they have fully recovered.

If someone is unresponsive or unconscious and you do not have access to a glucagon injection, call emergency services immediately.

What to do if your blood sugar is high

If your blood sugar is high, there are several steps you can take to manage and lower it. Here are some detailed instructions and tips to help you address this issue:

Understand the Causes

Firstly, it is important to understand the potential causes of high blood sugar. High blood sugar, or hyperglycemia, can occur when your body doesn't produce enough insulin or becomes resistant to insulin. This resistance can be caused by a buildup of excess dietary fat in cells that are not meant to store fat. As a result, your body may need to release more insulin to compel your cells to accept the blood glucose.

Adjust Your Diet

One of the primary ways to manage blood sugar is through your diet, specifically by reducing your carbohydrate intake. Carbohydrates have a direct impact on blood glucose levels. When you consume carbs, they break down into simple sugars in your body, leading to an increase in blood glucose. By limiting your carb intake, you can help stabilise blood sugar levels. Focus on consuming more fibre-rich, complex carbohydrates found in whole foods like fruits, whole grains, and vegetables. These foods provide key nutrients and are broken down more slowly, giving your body a chance to process them effectively.

Additionally, it is important to be mindful of your fat intake. While the keto diet emphasises a high-fat, low-carb approach, excessive fat consumption can contribute to insulin resistance. Aim for heart-healthy fats like olive oil and nuts, and avoid excessive saturated fats.

Test Your Blood Sugar Regularly

It is important to regularly test your blood sugar levels, especially if you are on the keto diet or making dietary changes. Blood glucose monitors are easily accessible and relatively affordable. Testing your blood sugar will give you valuable insights into how your body responds to specific foods and activities. Consider testing at the same time each day to ensure your body is in a similar fasted state for consistent results.

Consult Your Doctor

If you are experiencing persistently high blood sugar, it is crucial to consult your doctor. They can help you interpret your blood sugar readings and make personalised recommendations. Your doctor may also suggest testing your fasting insulin levels along with your fasting blood glucose to gain further insights into your condition. Additionally, they can guide you in adjusting your diet and lifestyle habits to effectively manage your blood sugar.

Manage Stress

Stress can have a significant impact on blood glucose levels. Prolonged exposure to cortisol, the stress hormone, can lead to increased blood glucose. Therefore, finding healthy ways to manage and reduce stress is essential. This may include practices such as yoga, meditation, or engaging in activities that promote relaxation and improve sleep quality.

How to personalise your diet based on blood sugar response

Personalising your diet based on your blood sugar response is a recommended way to manage your health, especially if you are living with diabetes. The foods that raise blood sugar levels differ from person to person, so it is important to understand how your body responds to certain foods and adjust your diet accordingly.

To do this, you can monitor your blood sugar levels throughout the day, particularly after meals, to see how your body responds to different foods. This can be done through regular blood glucose testing, which can be done at home with urine strips. By tracking your blood sugar levels, you can identify which foods cause spikes or drops in your blood sugar.

For example, if you find that your blood sugar levels rise sharply after consuming white bread, you may want to reduce your intake of refined carbohydrates. On the other hand, if fatty fish or nuts are found to stabilise your blood sugar levels, incorporating more of these foods into your diet may be beneficial.

It is important to note that personalising your diet based on blood sugar response should be done under the guidance of a healthcare professional, such as a doctor or registered dietitian, to ensure that your dietary choices are safe and aligned with your health goals. Additionally, personalising your diet is just one aspect of managing blood sugar levels, and factors such as physical activity, sleep, and medication can also play a role.

Frequently asked questions